The present applicant previously proposed, for example, a layered material including a ceramic layer and a metal layer. Specifically, the present applicant proposed a layered material including a ceramic sheet formed of a spark plasma sintered compact of ceramic powder, and metal layers provided on both surfaces of the ceramic sheet, each of the metal layers being formed of a spark plasma sintered compact of metal powder, which layered material is produced through a method in which the metal layers are formed, through spark plasma sintering of metal powder, on both surfaces of the ceramic sheet which has been formed in advance (see Patent Document 1).
However, in the case of the layered material described in Patent Document 1, since the metal layers are formed, through spark plasma sintering of metal powder, on both surfaces of the ceramic sheet which has been formed in advance, reduction in volume of the metal powder during spark plasma sintering must be considered, and productivity may be reduced in consideration of improvement of the dimensional accuracy of the metal layers in a thickness direction. In addition, both surfaces of the thus-produced layered material may exhibit poor flatness, due to reduction in volume of the metal powder during spark plasma sintering. In such a case, the layered material requires finishing treatment through a sizing process (e.g., polishing).